NRS™ Needle Control Valves

Low Flow Gas & Liquid Flow Control Valves

Models 8503F / 8504F

The Brooks® NRS™ (non-rising stem) flow control valves are designed specifically for extremely low flow gas and liquid applications. Straight and 90° angle pattern models in stainless steel are available. Ideal for rotameters with needle valves, the line allows needle valve flow control by adjusting a sliding tapered needle. This prevents sticking caused by foreign matter in the fluid. These flow control valves are particularly suitable for precise control requirements and possess a high turns-to-lift ratio. The flow is constant for any given stem position.

Six needles with different tapers provide a wide choice of flow ranges. Needles and orifices can be changed without removing the valve body from the line (two different orifices are used, one for needle sizes 1-3, another for sizes 4-6).

Features

Smooth non-reversing flow characteristics
Constant flow at any given stem position
Fifteen turns full open to full close provides high turn-to-lift ratio for excellent resolution
Six interchangeable needle tapers, each increases capacity by an approximate factor of three
O-ring seal cannot be damaged by overtightening
Panel mounting nuts included as standard
1/8″ NPT connections integrally machined into body

For Use With

Mass Flow Meters
Variable Area Flow Meters

Specifications

Product Type	Valve
Differentiator	Designed for Extremely Low Flow Applications Straight and 90° Angle Pattern Models Available Wide Choice of Flow Ranges
Flow Range (Full Scale Capacity)	See Capacities & Pressure Drops Table in Data Sheet
Max Pressure	Stainless Steel Model: 1000 psig
Max Temperature	Stainless Steel Model: 250^oF (120^oC)
Connection Types	Standard: 1/8″ female NPT – integral Optional: 1/8″, 1/4″ compression fitting; 1/4″ female NPT; 1/4″ ID hose type adaptors
Dimensions	See Dimensions Figure
Materials of Construction	Body 316 Stainless SteelOrifice Size 1-3: Stainless steel and Teflon®; Sizes 4-6: Stainless SteelValve Needle 316 Stainless Steel Plunger Stainless Steel O-Rings Viton® fluoroelastomers